Multi-plate homogenizers tend to have several drawbacks (with the following discussion referring to FIGS. 1 and 2 of U.S. Pat. No. 6,244,739 as an example). First, crevices are exposed to the fluid product (for example, the crevices seen between items 44 and 32, 32 and 33, 32 and 4, and between the valve plates). Product that remains in the crevices may not be adequately removed during cleaning, and can lead to microbe growth and product contamination issues.
Second, such homogenizers have springs (for example, wave springs 50) in grooves formed on the faces of adjacent stacked valve plates. When the springs expand, they (and the grooves) may be exposed to the product, making the residual product resistant to subsequent cleaning.
Third, such homogenizers rely on the springs between the valve plates to maintain alignment of the valve plate stack. However, due to variation in spring diameters, it is difficult to maintain concentricity of the neighboring valve plates, and clearances arise between the valve groove and the spring. This is particularly true if plates wear or break. Misalignment affects the effectiveness of the homogenization process, and additionally increases the likelihood of the valve stack's failure (for example, owing to force imbalances and/or compression on misaligned valves). What is needed is a homogenizer that addresses these and other drawbacks.